Add concept BlobAllocator

include/llama/Allocators.hpp

@@ -28,7 +28,7 @@ namespace llama::allocator
         }
     };
 #ifdef __cpp_concepts
-    static_assert(StorageBlob<decltype(Stack<64>{}(0))>);
+    static_assert(BlobAllocator<Stack<64>>);
 #endif
 
     /// Allocates heap memory managed by a `std::shared_ptr` for a \ref View.
@@ -46,7 +46,7 @@ namespace llama::allocator
         }
     };
 #ifdef __cpp_concepts
-    static_assert(StorageBlob<decltype(SharedPtr{}(0))>);
+    static_assert(BlobAllocator<SharedPtr<>>);
 #endif
 
     template <typename T, std::size_t Alignment>
@@ -102,6 +102,6 @@ namespace llama::allocator
         }
     };
 #ifdef __cpp_concepts
-    static_assert(StorageBlob<decltype(Vector{}(0))>);
+    static_assert(BlobAllocator<Vector<>>);
 #endif
 } // namespace llama::allocator

include/llama/Concepts.hpp

@@ -27,6 +27,13 @@ namespace llama
         // other types
         std::is_same_v<decltype(b[i]), std::byte&> || std::is_same_v<decltype(b[i]), unsigned char&>;
     };
+
+    // clang-format off
+    template <typename BA>
+    concept BlobAllocator = requires(BA ba, std::size_t i) {
+        { ba(i) } -> StorageBlob;
+    };
+    // clang-format on
 } // namespace llama
 
 #endif

include/llama/View.hpp

@@ -41,7 +41,11 @@ namespace llama
     /// view's underlying memory, the specified allocator callable is used (or the default one, which is \ref
     /// allocator::Vector). The allocator callable is called with the size of bytes to allocate for each blob of the
     /// mapping. This function is the preferred way to create a \ref View.
+#ifdef __cpp_concepts
+    template <typename Mapping, BlobAllocator Allocator = allocator::Vector<>>
+#else
     template <typename Mapping, typename Allocator = allocator::Vector<>>
+#endif
     LLAMA_FN_HOST_ACC_INLINE auto allocView(Mapping mapping = {}, const Allocator& alloc = {})
         -> View<Mapping, internal::AllocatorBlobType<Allocator>>
     {